Oni: Never Just Red Demons

What are oni?

Ask for an oni and most people will describe the same thing: a large figure with horns, fangs, red or blue skin, a tiger-skin loincloth, and an iron club. It is one of the most familiar images in Japanese culture.

It is also a composite, built up over more than a thousand years from things that were not originally the same. The word oni (鬼) has meant several different kinds of being, and the familiar demon is what remained when they were laid on top of each other.

A spirit that does not appear

The Wamyō Ruijushō, a Japanese dictionary of the 930s, explains oni as something that hides behind things and does not wish to appear — a spirit of the dead. The earliest oni had no body to draw.

The Kokugakuin University encyclopedia of Shinto groups early ideas of oni into three types: evil spirits and malign kami, bringing disease and death; oni as foreigners or strangers; and oni as beneficent kami. The first type, it notes, was originally invisible and only later given a visible form.

Wardens of hell

The visible oni came largely from Buddhism. As teaching on the six realms and the torments of hell spread in the late Heian period, paintings such as the twelfth-century Jigoku Zōshi, the hell scrolls, showed hell’s wardens at work: muscular, fanged, sometimes with the heads of oxen or horses, punishing the dead.

Those wardens gave the invisible oni a body.

Mountains, gates, and outsiders

In medieval tales and performance, oni moved into the world. They lived on mountains and at city gates, attacked travellers, carried off women, and were hunted by heroes — Shuten-dōji on Mt. Ōe, Ōtakemaru on Mt. Suzuka.

The same word was also used of people: outsiders, those who would not submit to the court, anyone placed beyond the edge of the ordered world. That usage is part of the history of the word, and it is one reason the oni of the tales so often live just beyond a border.

The figure who changed sides

The year-end rite of tsuina, adopted from China and recorded at court by 706, drove out the invisible oni of disease. The person who did the driving was the hōsōshi, a figure in a four-eyed mask.

By the end of the Heian period, the National Diet Library notes, the roles had reversed: the hōsōshi himself was treated as the oni and chased out by the courtiers. The masked exorcist had become the demon. Later still, the rite merged with Setsubun and the throwing of beans — “oni out, fortune in.”

Appearance

Horns, fangs, wild hair, red or blue skin, a loincloth of tiger skin, an iron club. The horns and tiger skin are often explained by the northeast, the direction of the ox and the tiger, from which misfortune was said to come. Every element was added somewhere along the way.

Our illustration stacks the layers: the familiar red mask, the four-eyed mask of the rite, the shadows, and a gate.

Behavior and abilities

That depends on which oni. Invisible bringers of disease; punishers in hell; mountain bandits and kidnappers; sometimes protectors and bringers of blessing.

Weaknesses and countermeasures

Peaches, in the oldest Japanese chronicles; the masked exorcist of the year-end rite; beans at Setsubun; heroes with divine help. Each answers a different oni.

Layers and later imagery

Documented history. An invisible spirit of the dead in the Wamyō Ruijushō (930s); evil spirits, outsiders, and beneficent kami in early belief; the wardens of hell in twelfth-century Buddhist painting; monsters of mountain and gate in medieval tales; and the tsuina rite, whose exorcist became the oni by the late Heian period.

Later imagery. The modern oni is cheerful as often as frightening — a Setsubun mask, a mascot, a cartoon with a club — and is usually presented as a single species of Japanese demon.

It was never one thing. Its shape was built across centuries, by people trying to give a body to whatever they feared was just outside.